Abstract: Objective To explore the clinical value of CT enterography (CTE) and fecal calprotectin (FC) in assessing the activity of Crohn disease (CD). Methods A total of 76 patients who were diagnosed with Crohn disease at the Affiliated Hospital of Yangzhou University from April 2018 to January 2024 were selected and their clinical data were collected for retrospective analysis. According to the Simple Endoscopic Score for Crohn Disease (SES-CD), the patients were divided into three groups: remission (n=20), mild activity (n=23), and moderate-to-severe activity (n=33). Quantitative parameters related to CTE were measured. The platelet, lymphocyte, and neutrophil counts in peripheral blood samples were determined by sheath flow impedance method, and the platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) were calculated. Fecal calprotectin (FC) levels were measured using fluorescence immunochromatography. Results SES-CD was highly positively correlated with bowel wall thickness and venous phase CT value (r>0.7, both P<0.001), moderately positively correlated with venous phase ΔCT, arterial phase CT value and arterial phase ΔCT (r>0.5, both P<0.001), and highly positively correlated with FC (r=0.883, P<0.001). Significant differences were observed in bowel wall thickness, arterial phase CT value, venous phase CT value, and venous phase ΔCT between the remission and mild activity groups and between the mild activity and moderate-to-severe activity groups (P<0.05). There were also significant differences in FC between the remission and the mild activity groups, and arterial phase ΔCT and FC between the mild activity and moderate-to-severe activity groups (P<0.05). The combination of bowel wall thickness, venous phase CT value and FC showed the highest AUC in assessing Crohn disease activity (AUC=0.993, 95%CI 0.903-1.000). Conclusions The combination of quantitative CTE parameters and FC can effectively assess Crohn disease activity.